As a diagnostic apparatus that observes three dimensionally an inside of a body of a subject body by utilizing an X-ray that penetrates a human body, an X-ray CT apparatus, a cardiovascular X-ray diagnostic apparatus, a digital tomosynthesis system, and the like can be taken.
The X-ray CT apparatus uses various tomographic images of the subject to reconstruct a complete 3D structure. However, the X-ray CT apparatus has a rotation mechanism for scanning and is thus not suitable for radiography of a fast moving organ, such as heart. Thus, an attempt is made to increase a scan speed by increasing the number of rows of detector elements and rotating speed. However, a radiography range is still narrow, and a video image of 30 frames per second cannot yet be acquired. At present, even an apparatus providing a high scanning speed can acquire an image of nothing more than 3 frames per second. In addition, the X-ray CT apparatus irradiates the entire circumference of the subject with an X-ray to photograph about 600 to 1,800 X-ray images per one rotation, disadvantageously increasing exposure dose. Further, scanning is performed in a state where a patient is lying on a bed, so that an image cannot be acquired from a patient in a standing position. This poses a problem that correct diagnosis cannot be made for a part at which a position of internal organs or a status of joints is changed by influence of gravity.
The cardiovascular X-ray diagnostic apparatus can acquire a video image of 30 frames per second. Further, the cardiovascular X-ray diagnostic apparatus performs X-ray irradiation from nothing more than two directions at most (double-arm type), so that the exposure dose is lower than that in the X-ray CT apparatus. However, in order to grasp a 3D structure of the subject from two X-ray images obtained by irradiation of different angles, an operator is required to have anatomical knowledge and technical skill.
The digital tomosynthesis system is a system that is obtained by digitizing an X-ray tomography and can synthesize tomographic images of the subject with low exposure dose. However, the digital tomosynthesis system is not suitable for kinetics observation of fast moving organs or joints due to a mechanism of mechanically moving an X-ray source. An object of an embodiment of the present invention is therefore to solve the above problems and to provide an X-ray diagnostic apparatus capable of providing a stereoscopic video image while reducing exposure dose.